It is proposed to study the role of cyclic AMP and protein phosphorylation in nervous tissue. One approach is to use antibodies to a synaptic membrane protein to verify its synaptic localization and to set up a radioimmunoassay method for this synaptic membrane protein. A second approach is to pharmacologically characterize a histamine-sensitive adenylate cyclase in brain. A third approach is to evaluate the possible role of calcium-dependent protein phosphorylation in the regulation of neurotransmitter release in synaptosomes. A fourth approach is to purify and characterize the protein kinase associated with microtubular proteins in brain.